Protective Effects Of Ginsenoside Re On Synaptic Injury Induced By D-galactose Combined With ADDLs

Objective:The pathological features of Alzheimer's disease(AD)are complex,and the accumulation and deposition of A? is the primary link in inducing the pathological process of AD.There is increasing evidence that soluble Ap oligomers(ADDLs)are considered to be a major contributor to neurotoxicity.Aging is one of the major risk factors for neurodegenerative diseases,and D-galactose can induce brain aging,thereby affecting the function of neurons and leading to memory damage.Therefore,we first selected D-galactose-induced aging,combined with soluble Ap oligomeric to induce synaptic damage,and found the anti-aging Chinese medicine and its corresponding monomer thro?gh the life experiment of C.elegans acting on the above model,to study its mechanism of Protecting neurons and enhancing learning and memory.In addition,APP/PS1 transgenic AD mice were used to further verify its protective effect on synaptic structure,memory and emotional behavior.Methods:(1)C.elegans dr?g screening:in this study,the effects of five traditional Chinese medicines Radix Rehmanniae,Radix Rehmanniae Prepared,ginseng,asparagus cochinchinensis and achyranthes bidentata on the lifespan of N2 wild type were studied.The traditional Chinese medicine with extended life and its corresponding monomer were screened for further experiments.(2)Neuron experiment(in vitro experiment):A?1-42 was used for incubation and identification,soluble ADDLs oligomer was obtained,and D-galactose was combined to act on cortex neuronal cells.Morphology was observed under microscope,cell activity was detected by MTT method,and its effect on synaptic protein expression was further detected by Western Blot.(3)D-galactose and ADDLs joint induced damage experiment(in vivo experiment):the first intraperitoneal injection of D-galactose,and then,the combination of lateral cerebral ventricle injection ADDLs method to establish synapses damage of AD model mice,and to give ginseng saponin Re treatment,monitoring weight every week,of synaptic damage thro?gh behavioral science experiment to explore the spatial learning and memory in mice,the influence of fear memory.The protective effect of ginsenoside Re on synaptic proteins induced by galactose and ADDLs in mice was detected by Western Blot.Finally,GC-MS analysis technique and multivariate data processing methods such as PCA and OPLS-DA were used to analyze the differential metabolites in mouse serum,so as to find out the metabolic pathways involved in regulation and protection.(4)APP/PS1 transgenic mouse experiment(in vivo experiment):Four months old APP/PS1 mice were given ginsenoside Re,the changes of body weight,blood glucose and oral glucose substitute were monitored monthly,and the changes of T-CHO,TG and LDL-C lipid metabolism indexes in the serum of the mice were also monitored.Finally,further exploration was conducted by using eotton tablet nesting and Morris water maze behavior experiment.Results:(1)Extend the service life of C.elegans to dr?g experiments,thro?gh the observation of C.elegans survival time after the treatment,we found that the water and alcohol extracts of Radix Rehlanniae,Radix Rehmanniae Prepared and ginseng are can prolong the life of C.elegans,the water and alcohol extracts of asparagus coclinchinensis and achyranthes bidentata root can not extend the N2 wild-type caenorhabditis elegans lifespan,from 0.5 mg/ml to instead of 5 mg/ml according to shorten worm life dose dependent effect.Life extension effect:ginseng>Radix Rehmanniae Prepared>Radix Rehmanniae,the biological activity of alcohol extract was greater than that of water extract,the maximum life extension of ginseng alcohol extract was 30.33%,and the monomers Rbl and Re in ginsenoside could significantly extend the life of C.elegans,ginsenoside Re showed the strongest effect in the dose range of the study.(2)The ADDLs were prepared by incubating Ap 1-42 polypeptides,and the formation of oligomers,trimer and tetramer,was confirmed by gel electrophoresis and rapid silver staining.In vitro cultured cerebral cortex neurons in mice showed a significant decline in activity and destruction of synaptic structure after the action of the final concentration of 30 mM galactose.When 30 mM galactose and 1?M ADDLs were combined to act on cortical neurons of mice for 48 h,the neuron cell bodies died and the cell activity further decreased.Western Blot results showed that 30 mM of D-galactose and 1 ?M of ADDLs combined cultured neurons could reduce the expression of NR2B protein and increase the expression of NR1 protein,but had no effect on the expression of AMPK protein,and the expression of AMPK phosphorylated protein was significantly reduced.(3)After intraperitoneal injection of D-galactose and ADDLs in the lateral ventricle,spatial memory of the injured mice was increased and brain learning and memory function was impaired.The administration of ginsenoside can effectively shorten the space exploration time of the mice to find the platform and protect the learning and memory ability of the mice.Mice in the model group injected with galactose intraperitoneally and ADDLs in the lateral ventricle showed damage of conditioned fear memory,and the low dose of ginsenoside Re could protect their fear memory.Ginsenoside Re can inhibit galactose combined with ADDLs to induce abnormal expression of synaptic proteins and synaptic function damage in mice.GC-MS analysis showed that the glutamate metabolic pathway was changed.(4)Ginsenoside Re had no effect on the body weight and blood glucose of APP/PS1 mice.Ginsenoside Re could correct the abnormal glucose metabolism of APP/PS1 mice,but could not completely reverse it.Ginsenoside Re can regulate abnormal lipid metabolism in mice by reducing serum cholesterol,triglyceride and low density lipoprotein levels in the serum.The low dose of ginsenoside Re effectively protected the spatial learning and memory ability and enhanced the nesting ability of mice.Conclusion:The lifespan of C.elegans could not be prolonged by both asparagus cochinchinensis and achyranthes bidentata,and the lifespan of C.elegans could be well prolonged by Radix Rehmanniae,Radix Rehmanniae Prepared and ginseng.The life extension rate of Radix Rehmanniae Prepared was higher than that of Radix Rehmanniae.The total saponins in ginseng as well as ginsenoside Rbl and Re in small doses can significantly improve the life span,and the elongation rate is lower than that of the whole crude dr?g extract,Re>Rbl>Total.We prepared ADDLs with A? 1-42 polypeptide,and MTT experiment confirmed that it has certain damage effect on neurons.Combined with D-galactose,it can fturther aggravate the damage of cells and synapses,and affect the expression of synaptic proteins,so as to successfully model damaged neurons.After intraperitoneal injection of D-galactose to accelerate aging in mice,combined with lateral ventricular injection of ADDLs,the mice showed obvious decline in learning and memory,fear and memory ability,and synaptic damage,which can be used as AD model mice.Ginsenoside Re has a significant protective effect on spatial learning and memory,fear and memory of AD mice.Meanwhile,ginsenoside Re regulated the abnormality of glucose metabolism,lipid metabolism and behavior in APP/PS1 mice.